Hmm a couple of questions based on what you said:
I have a Win2K Server with Active Directory on my network
but I am using workgroups (no domains) in my network.
If you have AD running you have a domain going by definition. That's what AD
does: it serves up domains.
Do the workstations believe they are part of a domain? On a 2000 or XP
workstation you could check by right clicking my computer, then checking the
network ID tab (that's the XP name, I forget the name of the tab in 2000).
It will say in there if you're in a domain or a workgroup.
I want to keep the workgroup groupings but do not want to
create a domain tree since this will require me to have
more than one server (DC) in my network.
Woah! That's not true. You can have a domain with one DC no problem. Is it
recommended? No, there's not as much redundancy, but there is nothign
stopping you from having a single DC domain. It's better to have a single DC
domain than no domain. Still ahead of the game if you ask me.
Administrative work is virtually impossible with over 100
computers on my network.
Yup, a domain would resolve this.
~Eric